British and European Standards for Heritage and Conservation

Tim Yates

The wide variation in the standards and codes of practice which affect business in Europe are seen by
the Council of Europe as a barrier to trade between member states. Existing British Standards and
those of other countries are therefore slowly being replaced by new European-wide standards.

Is it safe? Is it strong enough? Will it last? These are the issues addressed by European Standards.
Standardising thatching materials might be a useful means of improving quality of some materials, although the question of whether a material is appropriate is another issue.

If you search on the British Standards website
for standards and codes of practice related
to conservation then, once the references to
energy are discounted, there are, as expected,
few relevant ‘hits’. At a national level there
is guidance on good practice – for example
in the UK there is the code of practice for
the cleaning and surface repair of buildings
(BS8221 Parts 1 and 2) as well as BS7913
which deals with the conservation of buildings
in general. With more careful searching it
is possible to find a considerable number that may have some bearing on building
conservation – for example those relating to
the testing of natural stone or the specification
of mortars – but few, if any of these are written
with conservation in mind.

The original purpose of standards was
to ensure that fixtures and fittings were of a
consistent size and quality but over the past
100 years the purpose has shifted towards
providing a minimum quality and making
sure that methods and materials reflect
good practice. Standards and codes of practice
allow specifications to be written in a clear and
concise way. They can also be used to support
accreditation schemes for conservators and
building conservation craftsmen.

There are currently a wide range of
test methods established by CEN (Conseil
Européen pour la Normalisation, the
European standards authority) and others such
as ASTM (the American Society for Testing
and Materials – one of the US standards
organisations) which are relevant to the testing
of individual materials (for example stone or concrete) or their conservation treatment
(for example UV testing of coatings). There
are also tests drafted by international groups
such as RILEM (the International Union of
Laboratories and Experts in Construction
Materials, Systems and Structures – see the inset
box further down this page) on the characterisation of materials, for
example historic mortars. However, there
are far fewer standards for the assessment
of combinations of treatments (for example
cleaning and consolidation) and composite
units (for example masonry walls). The
plethora of existing test methods makes it
essential that any new committee accepts
these and restricts its activity to producing
methodologies for the application of existing
tests to heritage materials and, if possible,
providing some guidance on the interpretation
of the results that are obtained.

EUROPEAN STANDARDS AND
CONSTRUCTION PRODUCTS DIRECTIVE

European standards are a key part of the
Construction Products Directive which
was conceived as a way of breaking down
artificial barriers to trade and so produce an
‘open market’ throughout the EU countries.
However, it has become clear that European
standards have the potential to raise additional
barriers if they are formulated in any way
that favours one country or one sector of
the industry. There is also a danger that the
standards can overprotect the consumer at the
expense of the producer.

Like all European standards, those for
construction materials have three parts; an
agreed and harmonised set of specifications
and test methods, an agreed system which
sets out who is responsible for carrying out
the tests and assessments, and a method for
evaluating (or checking) that everything is
being done correctly.

In the case of natural stone and some other
products, the manufacturer is able to declare
his results but still requires an ‘agent’ – usually
an independent laboratory approved by CEN
– to affix the ‘CE’ mark. The CE mark, which
is displayed on the product or its packaging,
shows that the product has been tested to an
agreed specification and allows it to be placed
on the market. In many countries once the
relevant specifications are in place it becomes
a legal requirement to apply the CE mark to
qualifying products.

The CE mark is not a quality mark since
it demonstrates a compliance with a minimum
requirement, although it still seems to be
mistaken for one. It must be remembered
that the driving force behind the European
standards is the need to fulfil the demand
from the EU (via CEN) for CE products
within certain ‘product family groups’ and
that there has been no requirement to raise
standards of work or even the quality of
individual products.
The three key questions which should be
answered by the European standards are:

Is it strong enough?

Is it safe?

Will it last?

These three questions are equally relevant to
building conservation – particularly ‘will it
last’ – but they need to be considered against
the all-important question: is it appropriate
to the existing building or structure? It is this
consideration that sets conservation apart
from the ordinary run-of-the-mill CE marked
products.

The whole process of drafting and agreeing
European standards seems to have taken a very
long time – more than 10 years for natural
stone and masonry products. But now many
of the test methods have been approved and
issued as European standards by BSI in the UK
– these are usually called ‘BSENs’. In addition,
the first of the specifications, for example those
for paving, setts and kerbs, have been accepted
and we are now in the official ‘transition’
period prior to the withdrawal of national and
other standards which have been superseded by
the new European standards. Occasionally, the
slow progress of European standards results in
a national standards organisation asking CEN
for permission to develop its own national
documents and this is usually accepted
provided that the national documents will not
conflict with European ones.

THE PRINCIPAL STANDARDS ORGANISATIONS

ASTM – American Society for Testing and Materials is one of the main standards organisations
for the US, Canada and the Pacific Rim countries.

BRE – Building Research Establishment is the UK’s leading centre of independent expertise
on building and construction and the prevention and control of fire. This expertise is available
to all in construction and associated industries, from multi-national companies and government
departments to individual designers, builders and building owners and users. BRE provides
independent and authoritative advice relevant to every stage of the life cycle of a structure from
design, through construction and use, to demolition and recycling.

CEN – Conseil Européen pour la Normalisation is the organisation set up by the EU to
implement the Construction Products Directive. CEN’s mission is to promote voluntary technical
harmonisation in Europe in conjunction with worldwide bodies and its partners in Europe. It is
envisaged that harmonisation will reduce trade barriers, promote safety, allow interoperability of
products, systems and services, and promote common technical understanding.

RILEM – Réunion Internationale des Laboratoires d’Essais et de recherche sur les
Matériaux et les constructions – the International Union of Laboratories and Experts in
Construction Materials, Systems and Structures. This organisation is based in Paris and provides a
platform through which interested groups can develop ‘standards’ in areas of mutual interest.

PROPOSED EUROPEAN STANDARDS
FOR HERITAGE AND CONSERVATION

A proposal to form a CEN Technical
Committee to draft documents related to
'Standardisation in the field of conservation of
Cultural Heritage' was put forward by UNI
(the Italian National Standards Organisation).
This proposal has been accepted by CEN and
the committee is preparing to start work as
Technical Committee 346.

The Scope and Introduction of the
committee seem to be straightforward and
to be based on earlier work undertaken by
UNESCO. The Scope describes the very
wide range of applications covered by the
term ‘artefact’ – from ethnographic objects
to buildings. The Scope concludes with an
outline of five areas which the committee
believes standardisation activity on the
conservation of cultural heritage should deal
with. These are:

1. Terminology relevant to movable
and immovable artefacts, and to the
conservation of the artefacts and the
material constituting the artefacts

2. Guidelines for a methodological approach
to the knowledge of the artefacts and of
the materials constituting the artefacts,
of the deterioration processes, and of
preservation/conservation work

3. Test and analysis methods for the
diagnosis and for the characterisation of
the artefacts

4. Tests and analysis methods for the
evaluation of the performance of
conservation products

It seems clear that the proposal is potentially
very wide ranging and that it is influenced by
‘political’ factors – particularly at a European
level. Its overall vision is well illustrated by
a quotation from a European Parliament
document (STOA 2001) that standards are
required 'to provide vision, guidance and
guidelines for "best practice" at a European
level, such as scientifically-based protocols for
validating conservation work on monuments
and archaeological remains'.

Many countries provide some guidance
– usually focused to their own traditions and
environments but it is difficult to transfer
prescriptive methods from one country to
another, and even more difficult to gain
agreement from 19 countries.

THOUGHTS FOR THE FUTURE

With a general trend towards more European
standards, it seems only sensible that building
conservation also should develop standards and
codes of practice. However, there is always a risk
of standards being developed internationally
that do not reflect local (or regional) good
practice and which may also stifle innovation
and the development of new skills. Therefore,
the ‘industry’ must make sure that its views are
represented on both national and international
standards committees.

This
article is reproduced from The
Building Conservation Directory, 2003

Author

TIM YATES is the director of the Centre for Whole Life
Construction and Conservation at the Building Research
Establishment. He has expertise on the weathering of
building materials, effect of salt on natural stone and
mortar, long term performance of pavements and floors,
codes and standards for paving and flooring materials,
inspection and assessment of historic buildings and
structures, protection and conservation of natural stone.